Small Bivalve Surveys

• Research Theme
  Fisheries & Aquaculture
• Funded By

  DPIPWE and IMAS

• Principal Investigator

  Dr John Keane

• Contributor(s)

• Project Summary

  Three bivalve species are harvested in small commercial fisheries in north-eastern Tasmania with the high quality product sold on the Australian domestic market. The fisheries are Venus Clams (Venerupislargillierti) and Native Oysters (Ostrea angasi) from within Georges Bay, as well as Vongole Clams (Katelysia scalarina) from Ansons Bay.  

  IMAS assesses these fisheries every two years.  This involves surveys of the beds to estimate biomass, which is used to determine the allocation of quota for forthcoming fishing years. The Total Allowable Commercial Catch (TACC) for each fishery is generally set by DPIPWE at 10% of the total biomass estimated by IMAS. Management rules for each fishery also include minimum size and area restrictions.

  Biomass surveys by IMAS staff involve random sampling of quadrats from within the fished shellfish beds. Two to five thousand individual specimens are collected in these surveys and each is measured to estimate the size structure of the fishery. This size information provides information on whether there are enough smaller undersize clams or oysters to supply the fishery in future years.

  The total allowable commercial catch is not always harvested in these fisheries. This can occur for a range of reasons, most often because of market competition from fisheries interstate or overseas.

  Intertidal clams contribute to the diet of wading birds and the fishery harvest needs to be conservative to ensure that this ecosystem role is not affected.  The Native Oyster beds harvested in this fishery were once extensive across southern Australia but were depleted by dredging operations in the 19^th century.  The current Tasmanian fishery involves hand harvesting by divers and is considered sustainable.  

  The sustainability of the fisheries are reported through both Tasmanian fishery assessments and through the national Status of Australian Fish Stocks project (see links below).

  http://fish.gov.au/report/83-Venus-Clam-2016

  http://fish.gov.au/report/75-VONGOLES-2016

  Reports and Publications

  IMAS newsletters, reports and publications about our bivalve research are available on our Publications and Resources page, under the heading 'Other Tasmanian Fisheries'.

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